I should probably wait till closer to time to ask this question, but gotta know now.

Ok....i don't forsure know when, but i'm going to put 35's on my leveled 97 f150. Just wondering, right now i have 305/70-16's on my stock 7" wide rim. The edges of the back tires, where there isn't any weight in the bed aren't coming in contact with the ground/road so they're not really wearing on the edges that much. When i go to the 315/70-17's, im going to put like 01' lariat 17x7.5 wheels on the truck. I figure since the 315 is a little wider than 305, and the 305's don't wear about half-3 quarters of an inch on either side of the tire, i should go with a wider oem wheel. So i'm definently not putting the 315's on a 7" rim, i'll go with 7.5. I figure this will cut down on the non-wearing portion of the tires too since 10mm isn't quite half an inch they'll wear better, but a little awkward wear, im not worried about.
(sorry that's confusing kinda)

So going with a wider wheel(7.5"vs7") off a newer model lariat(01), i was wondering if i'll have any rubbing other than at full lock. i know it'll work with the oem 7", just like slightly rub the frame i think at full lock maybe the control arm some. Would this still be true with the 7.5 inch rim or would i need to stick with a 7" for it to work?
OR...Could i just trim a some on the lower valence piece and be alright? As long as i'm trimming NO metal (1997), im fine with the (plastic) trimming if need be.

Thanks

 

Yes, you can fit 315/70-17's (35x12.50) on your truck using the OEM 17x7.5 inch wide wheels. They will rub the frame slightly at full steering lock.
If your tires are not wearing at all on the outter edges, it is caused by the combination of the narrow 7 inch wide wheel and too much air pressure. Yes, your 305mm wide tires are wider than recommended for a 7 inch wide wheel, but you should be able to get pretty even wear by adjusting the air pressure. I'd run about 35 to 38 for daily driving.

 

it takes 22 lbs of air for my gfs 37x12.5x15 to run flat and wear even and 20lbs in my 39.5x13.5x15 to run flat so yea what wandell said is correct not disagreeing with him but with a rim that wide and that tire start out at running 35 and if the edges dont touch drop it down to 32 and so on..

 

Do the 7.5's have more backspacing than the 7"s, i guess? Where the engine weight is over the front tires they're wearing perfect in the front, but since there is less weight in the back, the edges are not wearing. I didn't wanna make it unsafe, so i just deflated them down to about 31psi on the back. They still aren't wearing on the edges. The only thing that i am afraid of is safety. I don't know how plausible it is i guess, but i know that tractor trailors have blow outs bc of under inflation. Where is the point that i have too low air pressure?

 

Both the OEM 16x7's and 17x7.5's have 4.5 inches of BS. I don't think I'd go below 32 psi for daily driving.

 

Alright, thanks wandell. I'm gonna keep them at about 32psi then. I figure if i keep them rotated back to front and so forth, they're gonna wear just fine.

Thanks for the info, i thought it would be okay. Just wanted to make sure with you since everyone is pretty much in agreement that your the expert on the subject. 7.5 is closer to factory specs so i'll feel better when i go to those.

Thanks